Find new coordinates of overlay object on the canvas after modifying on matrix in Android -

i'm working on android project , i'm using view class drawing image , overlays. i'm using code drawing image , circle (it working fine):

    @override      protected void ondraw(canvas canvas)      {                    super.ondraw(canvas);         if (!isinitialized) {             w = getwidth();             h = getheight();             position.set(w / 2, h / 2);              // scaling image fit screen             if(width<=height) { scale=((float)w)/width; } else { scale=((float)h)/height; }                      isinitialized = true;         }                        paint paint = new paint();         matrix.reset();            matrix.posttranslate(-width / 2.0f, -height / 2.0f);                     matrix.postrotate((float)(angle*180/math.pi));               matrix.postscale(scale, scale);              matrix.posttranslate(position.getx(), position.gety());                  canvas.drawbitmap(bitmap, matrix, paint);         canvas.concat(matrix);         canvas.drawcircle(testpoint.x, testpoint.y, 20, paint );     } 

now want show popupwindow windows tip on image , on same position of circle (testpoint). popupwindows not drawable object, how can find new coordinates of testpoint after scaling, rotation , translating put coordinates of popupwindow same.

i'm trying write code , working fine, rotation , translating without scaling, code wrote:

    int offsetx=(int) (-(width / 2.0f)+position.getx())+rc.left;     int offsety=(int) (-(height / 2.0f)+position.gety())+rc.top;      point rotatedpoint = rotatepoint(testpoint, centerpoint, angle);     rotatedpoint.x +=offsetx;     rotatedpoint.y +=offsety;     popup.update(rotatedpoint.x, rotatedpoint.y, -1, -1); 

where rc offset difference between bitmap view coordinates , screen coordinates.

and i'm tested rotatepoint function , working correctly.

note: when scale equal 1 (disable scaling) position of popup window updating correctly if rotate or move image.

how can merged scale (if not equal 1 only) equations?

or there way find new coordinates of overlay object on canvas after modifying on matrix?

please me solved problem. grateful help. thank you.

try use matrix.mappoints()

u must have absolute coordinates of image

how absolute coord?

void calculacoordenadasimagen(motionevent e){     float []m = new float[9];     matrix.getvalues(m);     float transx = m[matrix.mtrans_x] * -1;     float transy = m[matrix.mtrans_y] * -1;     float scalex = m[matrix.mscale_x];     float scaley = m[matrix.mscale_y];     lasttouchx = (int) ((e.getx() + transx) / scalex);     lasttouchy = (int) ((e.gety() + transy) / scaley);     lasttouchx = math.abs(lasttouchx);     lasttouchy = math.abs(lasttouchy); } 

then use 2 different arrays save points

int [] absolute = new int[2]; absolute[0]=lasttouchx; absolute[1]=lasttouchy;  int [] points = new int[2]; points = matrix.mappoints(absolute) 

in absolute u have absolute coordinates , in points u have points u want know

i wish help!